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Home , Breedon on the Hill, Charnwood Lodge, Chilcote, Copt Oak, Field Head, Grace Dieu Priory

Strategic Stone Study A Building Stone Atlas of

First published by April 2012 Rebranded by Historic December 2017

Introduction

Leicestershire contains a wide range of distinctive building This is particularly true for the less common stone types. In stone lithologies and their areas of use show a close spatial some parts of the county showing considerable geological link to the underlying bedrock geology. variability, especially around and in the north- west, a wide range of lithologies may be found in a single , located to the north-west of , building. Even the cobbles strewn across the land by the includes the county’s most dramatic scenery, with its rugged Pleistocene rivers and glaciers have occasionally been used tors, steep-sided valleys and scattered woodlands. The as wall facings and for paving, and frequently for infill and landscape is formed principally of ancient volcanic rocks, repair work. which include some of the oldest rocks found in England. To the west of Charnwood Forest, rocks of the Pennine Coal The county has few freestones, and has always relied on the Measures crop out around Ashby-de-la-, representing importation of such stone from adjacent counties (notably for the eastern edge of the -Leicestershire Coalfield. To use in the construction of its more prestigious buildings). Major the north-west of Charnwood lie the isolated outcrops of freestone quarries are found in neighbouring Derbyshire Breedon-on-the-Hill and , which are formed, (working Millstone Grit), and (both respectively, of and working Lincolnshire Limestone), and in (Bromsgrove) Sandstone. South of Charnwood Forest, a line (working Sand). Triassic Bromsgrove Sandstone can be drawn from Leicester to . To the west of this was extensively worked in some northern and western parts of line, the rocks that give rise to the gently undulating landscape the county, but additional stone may have come from are almost all of Triassic age, and comprise sandstones and and . The only other freestone red mudstones deposited in fluvial and semi-arid desert occurs in the east – the ochreous brown ‘ironstones’ of the environments. To the east, meanwhile, marine sedimentary Middle Lias (mid-to-upper Lower ), used in abundance rocks of Jurassic age crop out, the erosion of which has formed in local vernacular architecture. ridge and vale scenery, with and ironstones capping the hills and softer mudstones cropping out in the There are no active building stone quarries in Leicestershire, valley floors. and the county has never been a net exporter of building stone. The county’s hard igneous rocks are a noteworthy During the early Pleistocene, around 2 million years ago, exception, however, these being supplied mainly for modern day Leicestershire lay within the drainage basin of a kerbstones and paving setts – and also a minor amount of major river system – the Bytham River – which flowed building stone – from the early 19th century. Today, four eastwards to and out into the present North Sea area. quarries continue to supply aggregate for use throughout By the middle Pleistocene, glaciers advanced and retreated southern Britain, and one of them (Buddon Wood Quarry) will over the whole county, depositing sands and gravels, still provide small quantities for building and decorative use. laminated clays and unsorted till, forming a blanket over the older rocks. New river channels later cut through these The diversity of Leicestershire’s building stone heritage is unconsolidated glacial deposits, locally exposing the older reflected in its Roman architecture. Leicester was an important harder rocks, and ultimately giving rise to the distinct Roman town, and has one of the finest surviving Roman topographic features we see today. structures in Britain - the Jewry Wall. Decoratively built of courses of thin, locally-made Roman clay bricks and at least As noted at the outset, there is a close relationship between eight types of locally sourced rubblestone, it is an architectural the local geology and the selection of building materials. catalogue of the local stone resources. Generally, stone has been used close to its source, especially in the case of older buildings.

XXX Strategic Stone Study 1 Leicestershire Bedrock Geology Map

Derived from BGS digital geological mapping at 1:625,000 scale, British Geological Survey ©NERC. All rights reserved

Leicestershire Strategic Stone Study 2 Precambrian (Neoproterozoic) Lavas & Lava-Breccias

Charnian Supergroup The volcanoes that formed the rocks of Charnwood are thought to have had their magmatic centre close to the Charnwood Forest is an area of craggy hills, about 10 km wide, present day in the west of the forest. There are two located to the north-west of Leicester. Its relatively small associated volcanic complexes, each now the site of a large outcrops represent the exhumed topography of an ancient quarries, at Bardon and . The lavas are of andesitic or mountain range, the lower slopes of which remain buried dacitic composition, and have been quarried primarily to beneath the Triassic strata that now surround it. The rocks are supply aggregate to the south and east of England. This largely the products of explosive volcanic eruptions, and practice has been going on for well over a century, but these include lavas, volcanic breccias, conglomerates and tuffs. rocks have also been used locally as a building stone (albeit to Several igneous intrusions are also present. They were formed a limited extent) for much longer. between about 650 and 540 million years ago, and have been divided into three major stratigraphical units: the Blackbrook, Bardon Hill Volcanic Complex Maplewell and Brand groups. These collectively make up the Charnian Supergroup. Bardon Breccia This is best observed in the ornate 19th-century Bardon The older buildings, especially the medieval churches, tend to church, where it has been used as an angular rubblestone, include a wide variety of Charnian rock types. There are few (with Lincolnshire Limestone dressings), known to the pre-Victorian buildings in the centre of Charnwood, as the quarrymen as the ‘good-rock’. It is a dark green-grey, fine- Forest was originally a hunting reserve dating back to grained stone (andesite) that is indistinctly mottled in parts medieval times. With the exception of , all the (owing to its brecciated state). Staining of the joint surfaces, medieval churches and other structures are located on the gives the occasional block a dull dark red colour. Bardon periphery of the park. Only the Victorian and later churches Breccia is the building stone used at Bardon Church (below). tend to display a single stone type in their wall fabrics.

The Charnian rocks are very hard and are almost invariably used in buildings and walls as uncoursed, angular rubblestone. All of them are cleaved to some extent. The cleavage and joint planes determine the shape of the blocks, and these surfaces often weather to shades of red, brown or cream, quite different from the common greys and greens of the fresh stone. A single wall can, consequently, appear to be composed of several different stone types when it is actually built of just one or two with varying degrees of weathering.

When used as building stone, the ‘magmatic lithologies’ (lavas and intrusive rocks) are easier to identify than most of the varied fragmental volcaniclastic lithologies of the Charnian sequence. For this reason, the ‘magmatic’ stones have been named and described individually, while the volcaniclastic stones have been grouped by lithological type.

Bardon Church. Leicestershire Strategic Stone Study 3 The Old Covent in Whitwick is built of Grimley Andesite.

Whitwick Volcanic Complex

Grimley Andesite This andesitic lava occurs as a massive, weakly cleaved rock in and around Whitwick, and is exposed in small quarries in the centre of the village. The nature of the stone can be more easily examined at the Old Convent in Whitwick. Some enormous blocks have been used in the walls. The stone is very hard and fine-grained, and it commonly weathers to a strong red colour, although it may be mottled with the original dark grey-green shades still visible. It is used as rubblestone, in association with other local Charnian rocks, in building and Peldar Dacite Breccia in the walls boundary walls up to four kilometres away from its outcrop. of .

Peldar Dacite Breccia Weathered surfaces can appear uneven, showing a corrugated The large quarry at Whitwick, west of the village, is the source texture. Joint surfaces often weather to a cream or rusty brown of two distinctive stones: Peldar Dacite Breccia and Sharpley colour. Both stones have been used with other local stones Porphyritic Dacite. The former is a dark grey to greenish grey, across north-west Charnwood. Peldar Dacite Breccia is fine-grained lava enclosing ‘blobs’ of very similar coarser- conspicuous in the lower stage of the tower at grained lava with large crystals (phenocrysts) of quartz and church, and is also seen in nearby houses (up to several cloudy grey feldspar. The quartz crystals are unusually dark kilometres from Whitwick). It is also one of the stones used in and full of fractures. the walls of Mount St Bernard Abbey (above).

Leicestershire Strategic Stone Study 4 Charnian volcaniclastic sandstone is used in Blackbrook Farmhouse.

Sharpley Porphyritic Dacite Blackbrook Group This is best seen in the walls of Belton church. It is a fine- grained, pale grey to pale purple stone with large (up to 5 mm) ‘Charnian volcaniclastic sandstone’ phenocrysts of grey transparent quartz and cloudy grey The oldest volcaniclastic rocks crop out in central and north- feldspar. The distinctive features of this stone are the purple west Charnwood. These are assigned to the Blackbrook Group. hues and preferential weathering of the matrix, which leaves The term ‘Charnian volcaniclastic sandstone’ has been applied the larger crystals upstanding. Joint surfaces may be a cream to any sandstone, arenaceous mudstone or siltstone from this or brown in colour. unit. The stones are particularly dense, and show graded bedding and banding related to particle size variation (mud to Charnian - Extrusive sand-grade), which can result in colour banding, from pale Volcaniclastic Rocks grey to greenish-grey and dark-grey. They are a darker colour overall than the other striped Charnian stones, including the The Charnian volcanoes formed part of an island arc, and were ‘banded tuffs’ (described on p. 7). Use of Charnian explosively active (albeit intermittently) for several tens of volcaniclastic sandstone is notable in and around the village millions of years. Huge volumes of pyroclastic debris - ash, tuff, of , where the stone probably came from local and other fragmentary volcanic rocks – were erupted and quarries at Morley, Blackbrook and Newhurst. Charnian deposited in the surrounding sea. Together with finer volcaniclastic sandstone is used in Blackbrook Farmhouse sediments eroded from the flanks of the volcanoes, these built (above) and at St Marys Church in . up a great thickness of volcaniclastic sediments. Much of the material was sorted by grain size as it settled, giving a banded appearance to the rocks (particularly the finer beds of sandstone and tuff). Leicestershire Strategic Stone Study 5 Blackbrook & Maplewell Groups ‘Crystal tuffs’ are found throughout the Maplewell and Blackbrook groups (and therefore right across Charnwood), ‘Charnian volcaniclastic breccias’ although many are not strictly true crystal tuffs as they may Interbedded with the finer Charnian units are occasional beds also contain lithic or glassy fragments. The only ‘crystal tuff’ containing abundant angular to sub-rounded volcaniclastic that has been identified and named in a building is the rock fragments (2cm to >10 cm in size) set within a matrix of St Bernard Tuff, which was quarried on site and used finer debris. extensively in the Mount St Bernard Abbey and older surrounding buildings. A few angular blocks of such breccia can be seen in most building and field walls built of mixed Charnian rocks. The Maplewell Group colour of these stones varies, depending on the source, but they are often grey or greenish-grey. The larger clasts can be Volcanic Formation prominent owing to differential weathering of the components. ST BERNARD TUFF MEMBER

‘Charnian crystal tuffs’ St Bernard Tuff The fine-grained debris of a volcanic explosion can produce a This is a grey, massive, lithic-crystal tuff, used in the walls of rock comprising crystals and crystal fragments set within a Mount St Bernard Abbey into sub-angular slabs from 20cm to finer-grained matrix. Variable weathering of the mineral 90cm long. At outcrop, the rock unit passes up vertically into a components may produce a speckled appearance, although volcanic breccia and a thinly bedded, graded crystal tuff, but the overall colour is usually grey or grey-green. The general these lithologies are not evident in the abbey building stones. term ‘Charnian crystal tuff’ has been used in this study for any Weathered joint surfaces are cream and pale brown coloured. such stone, the precise geological source unit of which cannot There is a small quarry adjacent to the abbey and other small be determined when blocks are seen in isolation in a building. pits in nearby fields.

Mount St Bernard Abbey, built of Peldar Dacite Breccia and Mount St Bernard Tuff. Leicestershire Strategic Stone Study 6 ‘Charnian banded tuffs’ These are very hard, fine-grained, volcaniclastic rocks, made up of andesite and dacite clasts, with some volcanic ash. They are pale in colour, light grey or green when fresh, but often seen weathered to a creamy white or pale pink. At outcrop, they are typically thinly bedded or laminated, although massive in parts, and show a slight colour banding reflecting the grain size variation. The stone is poorly cleaved, and is sufficiently well indurated that it can only be broken along The crags of Beacon Hill are a good place to joint and cleavage planes to produce a sharply angular see ‘Charnian banded tuffs’ at outcrop. rubblestone. It is used in vernacular buildings and dry stone walls along with other Charnian rocks throughout the Charnwood area. The crags of Beacon Hill are a good place to see ‘Charnian banded tuffs’ at outcrop (top right).

Charnian - Intrusive Igneous Rocks

During the later stages of the Charnian volcanic activity, or shortly afterwards, two contrasting suites of igneous bodies were intruded into the accumulated volcaniclastic debris. In north Charnwood relatively thin (up to 60 m wide), near- North Charnwood Diorite is a minor vertical sheets of diorite (the North Charnwood Diorites) form component in the walls of St Botolph’s Church in Shepshed. NW–SE trending ridges in today’s landscape. The younger intrusions (the South Charnwood Diorites), solidified from a more silicic and calc-alkaline magma, and form a general mass several kilometres in extent around the southern edge of Charnwood, flanking the route of the A50 between Leicester and .

North Charnwood Diorites This very hard, dense rock forms the elongate hill tops west of , north of Bawdon Castle Farm, and at Buck Hill near Nanpantan. The northern-most outcrops were worked in Longcliffe and Newhurst quarries near Shepshed, where the stone can be seen as a minor component of the parish church walls. It is a very dark grey rock with abundant large, grey feldspar crystals set within a fine to medium-grained matrix, giving an overall mottled texture. North Charnwood Diorite is a minor component in the walls of St Botolph’s Church in Shepshed (middle and bottom right).

North Charnwood Diorite is a minor component in the walls of St Botolph’s Church in Shepshed. Leicestershire Strategic Stone Study 7 South Charnwood Diorites (‘Markfieldite’ & ‘ Granite’) The South Charnwood Diorites were quarried at several sites near and also a few kilometres to the south-west, near the village of Groby. The worked stone is a hard, massive, medium to coarse-grained igneous rock with a speckled appearance. From the mid-19th century, it has been principally quarried for and exported across southern England as aggregate, small paving setts and kerbstones. Locally, it was South Charnwood Diorite from Groby also used for building foundations, and as angular used in a cottage in . rubblestone, occasionally squared, in boundary walls, cottages and the two village churches, where differences between the stone from the two centres can be observed.

The church at Groby was built in 1840, when there was a small, busy quarry located immediately opposite (on what is now an industrial site). The main quarry at Groby, north-east of the village, was opened around 1880 by the Groby Granite Company Ltd, when the village quarry was worked out.

The stone in Groby church is predominantly dark pink in colour, comprising pink to red feldspars, grey to colourless quartz and minor amounts of dark ferro-magnesian minerals. South Charnwood Diorite from Groby was used in a cottage in Newtown Linford and in Groby church tower.

By comparison, the ‘Markfieldite’ stone in the 12th-century church at Markfield (extended and restored in 1865 after Markfield Quarry opened) is an overall darker grey colour. It is composed of green to grey feldspars set within a pink to grey South Charnwood Diorite from Groby matrix, and contains about 40-50 % dark-green to black used in a cottage in Groby church tower. ferro-magnesian minerals. The stone is now worked at the much larger Cliffe Hill Quarries nearby.

St Michael’s Church, Markfield uses Charnwood Diorite for its construction.

Leicestershire Strategic Stone Study 8 Brand Group

The Cambrian rocks of Leicestershire are found on the eastern Brand Hills Formation and southern fringes of Charnwood Forest. They are assigned STABLE PIT (QUARTZITE) MEMBER to the Brand Group (the uppermost part of the Charnian Supergroup), which is sub-divided into the Brand Hills and South-west of Leicester itself and across south-western formations. Leicestershire generally, a hard, medium-grained quartz arenite is infrequently seen in building walls (and even then, it tends to be a minor constituent). It is used in small, squared rubblestone blocks of uniform texture and pale grey colour.

Close to Leicester, where the stone may have a dull brown tint, it is thought that the stone came from the Stable Pit Quartzite, of which there are very small outcrops in and near to the villages of Groby and . In the south-west of the county, the blocks are more likely to have been sourced from the broadly contemporaneous Sandstone Formation of neighbouring Warwickshire.

Swithland Formation

Woodhouse cottage. Swithland Slate The youngest unit of the Brand Group – the Swithland Formation, but more commonly known as the ‘Swithland Slates’ - formed the basis of a thriving local industry during the 18th and 19th century. It consists of mildly metamorphosed silty mudstones and siltstones with an irregular, but closely- spaced cleavage, which allows the stone to be split. The less silty horizons were selected for thick, size-graded roofing slates, which were used county-wide and a little beyond. The remainder (and, in fact, the bulk) of the formation was used locally as a slabby rubblestone in building and boundary walls. The stone is dark grey, dark purple, dark green-grey and alms houses. very occasionally pale green where silty laminations occur in the mudstone. The main quarries were near to the villages of Swithland and Woodhouse Eaves in east Charnwood, and in south-east Charnwood at Groby. The industry declined with the arrival of the railways during the mid-1800s, which led to the import of cheaper and lighter Welsh slate. The last Swithland Slate quarry had closed by 1888. This attractive stone is still in demand today, but at present can only be obtained from recycled sources. Entire houses are built of Swithland Slate in the villages of Swithland, Woodhouse, and Woodhouse Eaves. Woodhouse Eaves house.

Leicestershire Strategic Stone Study 9 The church at Woodhouse Eaves stands directly above the historic Woodhouse Eaves Quarry (left). Thick Swithland Slates were commonly used in diminishing sized courses for roofing because the quarries were unable to produce sufficient single-sized slates. They therefore had to make full use of the variably-sized random slates available (middle left). This roof shows the contrast between Welsh slate at the top and Swithland slate lower down.

ORDOVICIAN & South Leicestershire Diorite Complexes

Plutonic igneous rocks of age, which are believed to be representative of a single intrusive episode, occur both to the north and south of Leicester. The magma chemistry Woodhouse Eaves Quarry. seemingly evolved through time, such that the resultant rocks are of variable composition, (ranging from granodiorite to diorite, and even gabbro in one quarry). They are referred to either the Mountsorrel (Granodiorite) Complex or the South Leicestershire Diorite Complex. These two intrusive complexes comprise medium to coarse-grained, hard, massive, crystalline rocks. The Mountsorrel Granodiorite (frequently, but inaccurately, known as ‘Mountsorrel Granite’) crops out to the east of Charnwood near the village of Mountsorrel, where there is a large active quarry (the stone being worked primarily for aggregate).

The South Leicestershire Diorites have relatively small outcrops to the south-west of Leicester, forming a line of hills from Enderby to . Of these, only the Croft outcrop is still being exploited, and the extraction is in the floor of the Swithland slates. exceptionally deep quarry. Several quarries have been infilled or flooded, while others have been abandoned or enclosed by urban development.

A good example of the range of colour, thickness and graded sizes used when roofing in slate. Leicestershire Strategic Stone Study 10 The relative proportions of quartz, feldspar and ferromagnesian minerals, and also the size of the constituent crystals, control the colour and texture of these speckled rocks. When seen as a building stone, the Mountsorrel rocks tend to be pale pink to dark red, while the South Leicestershire Diorites range from pink to purplish-grey. They are used as angular rubblestone, giving rise to a ‘crazy paving’ effect, although the blocks were occasionally squared. The stone is very hard, and has commonly been used for footings and foundations, but never for decorative carvings. In the 19th century, paving setts and kerbstones made of ‘Mountsorrel Granite’ were exported to towns across England. Many Victorian churches, village halls and houses were built or restored using these stones, and even in recent years they have been used for church extensions. The Mountsorrel stone is used in central north Leicestershire, and the quarries at Croft, Enderby and Sapcote supplied stone to the south and south-west of the county.

The Barrow-upon-Soar church tower, built of Mountsorrel Granodiorite.

Terraced cottages in Quorn, built of Mountsorrel Granodiorite and roofed with Swithland Slate. Leicestershire Strategic Stone Study 11 Carboniferous Ticknall Limestone Formation

Carboniferous rocks are found in the north-west of the county. ‘Grace Dieu Stone’ Inliers of the Lower Carboniferous Peak Limestone Group form There is a very small outcrop of the Ticknall Limestone the hills at Breedon and Castle Donington, while Upper Formation near to . This appears to have Carboniferous Coal Measures Group strata occupy much of the been worked and used to a minor extent, along with Charnian area around Ashby-de-la-Zouch (representing part of the rocks, in the old chapel walls of the building. The stone itself is Derbyshire-Leicestershire Coalfield). The limestones have been a very fine-grained, grey, massive limestone. Large bivalve used only to a very limited extent as a building stone, and fragments are common. It is simply used as an although sandstones do occur within the restricted Millstone angular rubblestone. Grit and Coal Measures sequences, none are known to have been worked locally for building stone. Cloud Hill Dolostone Formation

Peak Limestone Group ‘Osgathorpe Dolomite’ A very fine-grained, cream-coloured dolostone with fossil casts Carboniferous Limestone has been used as dressed and many small voids, it is used in association with a rubblestone in the church at Osgathorpe, at Grace Dieu Priory conglomeratic stone containing dolostone pebbles in the (ruinous), and in vernacular buildings in the village of Breedon church at Osgathorpe. Both stones are believed to have come on the Hill and the nearby hamlets of Tongue and Isley Walton. from the quarry on Barrow Hill, just above the village. The It is given several local names, depending on the area where it latter is described with the Triassic rocks. has been quarried and used. Carboniferous limestones in Leicestershire are mostly dolomitic, unlike those of Derbyshire.

Milldale Limestone Formation

‘Breedon Stone’ There are large, working aggregate quarries at and at Cloud Hill, yet there has been only limited use of the stone in local boundary walls and buildings. It is a hard, fine-grained, often red, dolostone with some fossil casts and rare traces of shell debris. It is used as an angular rubblestone and as squared, variably-sized dressed blocks, notably in a few decorative ‘rustic’ buildings. Although the stone is cream to pale fawn in colour when first quarried, coatings of lichen often Breedon Stone was used for a small memorial building on the make buildings look grey. Despite being perched on the hill green at Breedon on the Hill. directly above the quarry, the church at Breedon is built of Millstone Grit. Bromsgrove Sandstone and Bulwell Stone have also been used in its construction and conservation. Breedon Stone was used for a small memorial building on the green at Breedon on the Hill (right).

A close-up of the above building at Breedon on the Hill. Leicestershire Strategic Stone Study 12 Millstone Grit Group Millstone Grit sandstone has been used as a durable freestone, the ashlar blocks of which have sometimes been Morridge Formation sandstone given a decorative tooled finish. It is used extensively in all This is a hard, massive, medium to coarse-grained, grey to but the eastern parts of the county for dripstones and for fawn coloured, fluvial sandstone, composed mainly of repairs, particularly on quoins, buttresses and other rounded grains of quartz and feldspar, with scattered mica exposed elevations. flakes. It is variably cross-bedded and may show banding as a result of grain size variation. Breaks in sedimentation are The sandstone crops out near the village of , but indicated by very small quartz pebbles and rare thin layers of there is no evidence of it having been put into use there. It was ferruginous grains, which can give rise to a weak brown quarried just over the county boundary in , staining. The stone may have a speckled appearance. around Melbourne, Stanton by Bridge and at Dawson’s Rocks, to the north of Ashby-de-la-Zouch, but these sources are probably too far removed for it to have been used as a primary building material in Leicestershire during the medieval period. Its use in the county increased in the 19th century, and several Victorian churches and extensions in north and north-west Leicestershire are built entirely of Millstone Grit sandstone. The church at Old Dalby (left) and Emmanuel Church (below) in are excellent examples of the use of imported Millstone Grit sandstone during the 19th century.

The church at Old Dalby.

Emmauel Church in Loughborough.

Leicestershire Strategic Stone Study 13 Kidderminster Sandstone is the probable source of the red and yellow ashlar sandstone used in Ashby-de-la-Zouch Castle.

highest points remaining as rugged, upstanding tors. Screes Triassic developed in places against the areas of high ground, while fluvial, lacustrine and aeolian deposits accumulated towards Sedimentary rocks of Triassic age accumulated, for the most the basin centres. Erosion and burial of the upland areas was part, in a semi-arid desert environment, within an area of completed by late Triassic times, when marine and brackish significant, but reducing, topographic relief. They crop out water conditions prevailed during deposition of the marginal across western Leicestershire and comprise the Sherwood marine limestones and mudstones of the . Sandstone, Mudstone and Penarth groups. Sherwood Sandstone Group At the end of the Carboniferous, substantial earth movements resulted in the folding, faulting and uplift of the Carboniferous Kidderminster Formation succession. Subsequently the was a time of intense erosion across Leicestershire, although marine conditions ‘Kidderminster Sandstone’ prevailed to the north of . Thereafter, when The Kidderminster Formation - formerly known as the sedimentation resumed in the early Triassic, extensive river Polesworth Formation, and itself the former ‘Bunter Pebble systems deposited the coarse gravels, and then sands, that Beds’– was probably the source of the large ‘Bunter’ pebbles now comprise the Sherwood Sandstone Group. that are seen in buildings across the county (see Quaternary section ). The sandstones are yellowish-brown to brownish- Sedimentation continued during the Middle and Upper red, medium-grained and friable. They crop out south-west of Triassic, depositing the mudstone-dominated succession of Ashby-de-la-Zouch, and are the probable source of red and the Mercia Mudstone Group. Gradually the upland areas of yellow ashlar sandstone used in Ashby Castle (above) and for Charnwood and the isolated Carboniferous outcrops, with the repairs to churches in south and west Leicestershire. Leicestershire Strategic Stone Study 14 Bromsgrove Sandstone Formation

‘Bromsgrove Sandstone’ This is one of the most important building stones in the county. It is composed of fine to medium-grained, well-sorted quartz sand with small-scale sedimentary structures, including planar and cross-bedding and occasional convoluted bedding (probably the result of de-watering during compaction). It is generally pale green-tinted grey to fawn in colour, although some infrequently observed reddish-fawn to pale brick red This damage that can inflict on masonry. sandstones may also be from this formation.

It can be easily sawn and provided a good ashlar stone in large blocks up to 90 x 35 cm. Blocks are usually used with a flat finish, but occasionally dressed to give a textured surface with a flat, un-tooled margin. It is used in all parts of a building, but may be susceptible to boring by insects and, in exposed places, to damp, frost penetration and wind erosion leading to exfoliation and extreme honeycomb weathering in some instances.

‘Bromsgrove Sandstone’ is extensively used throughout west Weathering and exfoliation can Leicestershire, where it is the principal stone in many attack certain types of stone. churches. It has been used for quoins and decorative work in many of the rubblestone churches, and for repair work over a wider area. Notable examples are the churches at , , and , amongst many others. Bromsgrove Sandstone was used for the beautiful carving at (bottom right), the walls of which are of Charnian stones. The stone for the small church at Chilcote was quarried just 100 metres away; the small quarry can be seen at the roadside opposite.

The sandstone crops out around the margins of the Derbyshire-Leicestershire Coalfield, and has been quarried in the north-west of the county at Castle Donington and , where it was known as King’s Mill or Kegworth Stone. The King’s Mill Stone contains pebble bands making it unsuitable for decorative work. It can sometimes be difficult to distinguish Bromsgrove Sandstone from some of the finer- grained varieties of Millstone Grit, and locality of use offers no assistance since both stones would have had to travel some distance to be used in certain parts of Leicestershire. Generally, though, Bromsgrove Sandstone is finer-grained and a little more friable. Bromsgrove Sandstone was used for the carving at Ulverscroft Priory.

Leicestershire Strategic Stone Study 15 Shepshed Sandstone Member & Other Pebbly may be either randomly scattered or aligned in the cross Sandstones bedding. The pebbly sandstones represent a marginal facies of Pebbly sandstones are locally developed within the the formation, deposited by tributary streams draining the Bromsgrove Sandstone Formation. Lithologically, they are Triassic mountains. One such pebbly sandstone horizon, medium to coarse-grained, usually grey but occasionally containing small angular and rounded pebbles of Charnian pinkish sandstones, with sub-angular to rounded pebbles of a rocks, is known as the ‘Shepshed Sandstone’. It is a very few millimetres to over a centimetre in size; these are minor component of the church walls at Whitwick, Newtown compositionally variable, but mainly quartzo-feldspathic, and Linford and Shepshed. Similar rock is used in and churches.

Mercia Mudstone Group

This thick, mudstone-dominated, red-bed sequence accumulated in a hot, arid desert with ephemeral rivers and extensive playa lakes. The area was subject to periodic flash floods, which deposited thin, laminated, very fine-grained sandstones known as ‘skerries’. These occur throughout the sequence, and were used extensively in the older buildings and vernacular structures.

A close-up of a pebbly Triassic sandstone – this one includes small angular pebbles Gunthorpe Formation of eroded Charnian rocks.

‘Osgathorpe Conglomerate’ The ‘Osgathorpe Conglomerate’, recognised only in Osgathorpe village church, comprises pale buff, sub-rounded dolomite pebbles set within a weakly cemented, gritty dolostone sandy matrix. It is believed to have come from Barrow Hill Quarry, together with the Carboniferous Osgathorpe Dolomite. It probably occurs as a breccio- conglomerate within the Gunthorpe Formation, the pebbles being eroded from and deposited against the Carboniferous limestone hills in the Triassic desert.

A house at Orton on the Hill built entirely of Skerry. ‘Skerry’ sandstones The thinly bedded ‘skerries’ are composed of pale grey, finely laminated, very fine-grained dolomitic sandstone with thin, greyish green clay partings.

They are commonly finely cross-bedded and frequently show intense distortion and convolutions due to de-watering. The stone is used as thin rubblestone slabs.

A close-up of one of the walls of the above cottage at Orton on the Hill. Leicestershire Strategic Stone Study 16 Sandstone The grains are mostly of quartz with evenly scattered darker A ‘skerry’ sandstone cropping out locally to the north of grains. The stone is largely planar-bedded, but often shows Shepshed – the Diseworth Sandstone – has been used cross-bedding, with horizons of spheroidal cavities up to extensively as rubblestone in the church and village buildings 10mm across, infilled with clear, crystalline gypsum. in Diseworth, and in boundary walls towards . Stone for some of the village buildings is said to have been Arden Sandstone Formation dug from shallow pits in fields on the north-east side of Diseworth. One exceptionally large block has been laid with ‘HOLLYGATE SANDSTONE MEMBER’/ the bedding plane vertical, showing superb ripple marks. Most ‘DANE HILLS SANDSTONE MEMBER’ of the houses on Grimes Gate, Diseworth (below) have footings and garden walls built of the Diseworth skerry. Small outcrops of a distinctive stone used in central Leicestershire can be seen where it was once quarried in what A pale grey to yellow-grey, fine-grained sandstone has been is now Western Park in the western suburbs of Leicester. It is a used as a squared freestone in Diseworth church and in village pale grey to almost white, fine-grained sandstone with buildings along Hall Gate to the west. rounded grains, which are almost entirely of quartz. It is either massive or weakly cross-stratified, yielding dressed blocks of up to 1.0 m x 0.4 m in size. The stone develops a mid to dark grey weathering crust.

Most of the houses on Grimes Gate, Diseworth have footings and garden walls built of the Diseworth skerry. Leicestershire Strategic Stone Study 17 The ruins of Cavendish House, Abbey Park.

When this crust is breached, the sandstone becomes very JURASSIC friable, and it was sometimes crushed to produce building sand. ’Hollygate/Dane Hills Sandstone’ (also known as ‘New About 200 million years ago, sea levels rose, submerging the Parks Stone’ or ‘Upper Keuper Sandstone’) is found as a minor Triassic deserts of Leicestershire. Thereafter, marine conditions component in church walls from , just north of generally prevailed. At times, the water was sufficiently shallow Leicester, to villages a few miles south-west of the city. It is to enable the deposition of limestones, many of which are the best seen in Leicester itself, however, where it is a major source of the building stones that characterise the architecture component in St Nicholas Church and in the old castle walls. of the eastern half of Leicestershire. Exceptionally, it was used as the main building stone for the early 17th-century Cavendish House in Abbey Park (above), for Lower Jurassic which the stone is said to have been ‘recycled’ from the adjacent ruined abbey. Scunthorpe Mudstone Formation/Blue Penarth Group Lias Formation

Lilstock Formation ‘ limestone’ ‘Blue Lias’ is the traditional name for the basal strata of the ‘White Lias’ Lias Group. These rocks are now assigned to the Scunthorpe ’White Lias’ is the traditional name of the youngest limestone Mudstone Formation to the north of a line running roughly beds of the Triassic Penarth Group. The laterally impersistent from Loughborough to and to the Blue Lias beds range in thickness from a few centimetres to (exceptionally) Formation to the south of this. 3 metres over short distances, and occur sporadically in the north of the county. Use of the ‘White Lias’ as a building stone Both units comprise alternations of fine-grained, blue-grey to is similarly sporadic: it is used as partly dressed rubblestone in dark grey, micritic limestones and mudstones. The clay buildings or as rubblestone in field walls within and between content of the limestone varies, and those limestones with a the villages of Cotes, and , where it may high proportion of clay are slightly darker and weather with have been gathered from field brash. rounded corners. Leicestershire Strategic Stone Study 18 At outcrop, the limestone beds frequently have regular, It is not a major building stone in the county, and is rarely used close-spaced joints. Some of these have pyritic/calcitic for an entire building, but has been widely used for small scale coatings, which, when used as facings, weather to a brown repairs. Of the few houses in which ‘Blue Lias’ (in this case the colour. More commonly, however, percolating iron-rich water lowermost Barnstone Member of the Scunthorpe Mudstone forms patchy, pale cream coloured joint surfaces.. Formation) is the principal building stone, an outstanding example is Beveridge House in Barrow-upon-Soar (below). The more calcareous beds can be easily split by wedges. Weathering, often exposes sub-parallel lamination which is not Scunthorpe Mudstone Formation visible in the fresh rock, but very evident in the weathered building stones. are small, and concentrated on the Granby Member bedding planes.. The limestone is easily dressed to provide a blocky rubblestone, comprising thin slabs, 10-15 cm thick, ‘Wreake limestone’ which are often coursed according to size in buildings. The name ’Wreake limestone’ is herein informally applied to a series of dark grey, shelly (oyster-rich) limestones occurring The ‘Blue Lias’ limestone outcrop extends roughly north-south within the Granby Member of the Scunthorpe Mudstone through Leicestershire, to the east of the and along Formation around Hoby (in the Wreake Valley). These its tributaries. It was extensively worked at Barrow-on-Soar limestones contain very little clay matrix, and the shells stand and in the eastern part of Leicester for the manufacture of proud on weathered surfaces. ’Wreake limestone’ is used as a cement, and selected beds were quarried for diverse domestic rubblestone, occasionally squared, in building and boundary uses: wallstones, floor slabs, even the carving of stone sinks. walls, most notably in the church located within the grounds of College and the church at .

Beveridge House in Barrow-upon-Soar uses Blue Lias as the principal building stone. Leicestershire Strategic Stone Study 19 Fen Farm Limestone in the churchyard walls at .

‘ limestone’ Jurassic ‘ironstones’ This is a richly bioclastic, very pale grey to white limestone in which oyster shells again predominate. These form layers Historically, the name ‘ironstone’ is applied to rocks, usually separated by thin, calcareous clay partings and scattered, thin limestones or sandstones, which have a significant iron layers containing brown limonite grains. Other fossils present content (up to c. 30%). Leicestershire’s ironstones occur at two include thin, finely grooved echinoid spines (up to 20 mm different stratigraphic levels. The older ironstones sit within long) and pentacrinoid ossicles (2-3 mm diameter). The ‘Sileby the Lias Group (the Marlstone Rock Formation and the closely limestone’ occurs in thin slabs and is a weak, poorly cemented associated ‘Sandrock’ of the Dyrham Formation), which are stone, but is not, surprisingly, prone to surface weathering. extensively developed in the north-east of the county, capping Like the ‘Wreake limestone’, it is thought to come from within the higher ground, including the Belvoir escarpment. The the Granby Member of the Scunthorpe Mudstone Formation, younger ironstones, meanwhile, lie within the Northampton and has only been found used in the walls of Sileby church Sand Formation of the Inferior Oolite Group, which is limited and in garden walls in Hoton. to small hill top outliers around , Loddington and Nevill Holt in the south-east. Both are major In the villages of Hose and Redmile, a muddy micritic sources of building stone, and contain beds sufficiently limestone with large Gryphaea (the ‘Devil’s Toenail’) is used i enriched to have been worked as a source of iron. n the boundary walls of the churchyards. It probably gives rise to the proximal escarpment which bisects the Both of the Leicestershire’s ‘ironstone’ sequences were and is thought to be the Fen Farm Limestone of the deposited as shallow-marine, sandy sediments in which Granby Member. original carbonate particles such as ooids and shell fragments were replaced by the iron minerals siderite (grey iron carbonate) and berthierine (a green iron silicate).

Leicestershire Strategic Stone Study 20 The unweathered ironstones have a greenish-grey colour, and, Further complications arise if an attempt is made to very rarely, ‘blue-hearted rock’ can be seen where the core of a distinguish between the main building stones produced from block has been completely protected from effects of the Marlstone Rock and Dyrham formations. weathering. Secondary limonite (yellow-brown hydrated iron oxide) dispersed through the rock gives it a rusty appearance, ‘Middle Lias’ ironstones or is concentrated in ramifying or concentric box-like veins. Dyrham Formation ‘Sandrock’ Given that both ironstone sequences have a comparable & Marlstone Rock Formation genetic origin and mineralogy, it is not surprising that they Formerly grouped together as the ‘Marlstone Rock Bed’, work yield building stones of similar appearance, which can be very carried out by the BGS during recent years has allowed difficult to distinguish when they are removed from their separate Dyrham and Marlstone Rock formations to be outcrop. Each encompasses several lithologies – the sandy defined. During the 19th century, the ‘Marlstone Rock Bed’ was ironstones may be found in association with ferruginous described as a variable sequence of ooidal ironstones with fossiliferous limestones and, occasionally, the concentrated bioclastic limestones, which overlay beds of sandy limestone iron-rich stones. The Marlstone and/or ‘Sandrock’-derived known as the ‘Sandrock’. The upper part of the unit contained ironstones were principally used in the north-east of the beds of iron ‘ore’ quality, while the ’Sandrock’ beds were county, whereas the Northampton Sand-derived ironstones recognised as the ‘best building stone’. tended to be used in the south-east, although the boundary between the two is difficult to define. Generally, the Northampton In the current stratigraphical scheme, the ‘Sandrock’ is now Sand Formation produces stones with a wider range of separated and assigned to the Dyrham Formation, with the colours, including a distinctive purple-hearted variety. Both ‘upper’ part of the former unit being referred to as the varieties may be found in some villages, and even in a single Marlstone Rock Formation. building, especially in the central-eastern parts of the county.

An ‘ironstone’ house in , with a Swithland slate roof.

Leicestershire Strategic Stone Study 21 Dyrham Formation None of these building stones are worked in Leicestershire today. Consequently, repairs are usually undertaken with ‘Sandrock’ stone from the Marlstone Rock Formation quarries at Great The ‘Sandrock’ has an impersistent outcrop, thinning to the Tew, near Banbury. This ferruginous limestone has a low iron south, which can be traced from Belvoir almost to Tilton on the content and weathers to a pale ochreous brown, but in texture Hill; it has not been recognised south of Tilton. It is a calcareous it resembles Sandrock, with scattered shells, shell debris and and ferruginous sandstone with interbedded shelly limestones burrow traces. which have a sideritic muddy matrix. Across north-east Leicestershire, the Sandrock and indeed the sandy limestones of the Marlstone Rock Formation have been used as building stone.

It has proved impossible to routinely differentiate the two stones during this survey of buildings, and the term ‘Sandrock’ has therefore been used for all of this stone, except where fossil evidence has been found to confirm that the stone is from the Marlstone Rock Formation (in which case, it has been referred to as ‘Marlstone Rock’). This method of differentiation can be successfully employed in the villages of Billesdon, and .

The dominant Sandrock lithology is a yellow-brown, fine to medium-grained, limonitic sandstone, very slightly micaceous, with scattered shell debris and narrow vertical burrow traces. Belemnites and small bivalves are sparsely present, and brachiopods, particularly terabratulids, occur in occasional clusters or ‘nests’; these sometimes stand proud of surrounding weathered stone by as much as 10 cm. The rock was used as a freestone, but it is porous and readily suffers The Sandrock church at has original lancet windows in the tower from the effects of weathering in exposed settings. The stone and Sandrock buttresses, repaired with was used extensively for dressings in ‘ironstone’ churches, but Lincolnshire Limestone. few window and door dressings survive, having commonly been repaired with Lincolnshire Limestone.

Marlstone Rock Formation

Both the ‘Sandrock’ and Marlstone Rock ‘ironstones’ were probably worked from numerous small pits for building stone, but subsequent exploitation of the iron-rich beds (which sit above the building stone units) during the 19th century, lowered the surface of the fields, obliterating all trace of many of the stone quarries. Nevertheless, a few of the original building stone workings are still visible e.g. at Stone Pits Farm near Wartnaby and in the fields east of Holwell. The Marlstone Rock Formation contains several lithological variants, which are found as minor Sandrock brachiopod ‘nests’ standing proud where the remainder of the components in buildings and are described below. stone has weathered. Leicestershire Strategic Stone Study 22 ‘Marlstone ‘conglomerate’ There is a pebble bed at the base of the Marlstone Rock Formation which has occasionally found its way into rubble used as building stone. Well rounded, 1–7 cm diameter pebbles of limonitic and phosphatic mudstone, often slightly flat/discoidal in shape, occur within a finely comminuted shell-debris-rich, lime-matrix. The pebbles frequently have a thin dark brown rind. The stone can be seen as a very minor The paler ‘Sandrock’ can be seen In these component in association with other Marlstone Rock cottages in Holwell, constrasting with the lithologies in boundary walls in Tilton on the Hill and buildings dark Marlstone of the church opposite (seen below). in Harby.

Marlstone Rock ‘limestone’ a higher iron content, yielding a darker, red-brown building A hard, bioclastic limestone is found as a minor component in stone. It is seen in the Methodist church at Holwell (below). In association with other Marlstone Rock lithologies in villages the cottages opposite the church, the contrast between this between Harby and Tilton on the Hill, often occurring in lenses and the paler ‘Sandrock’ can be seen (above). within a single building stone block. Abundant crinoid ossicles and other pale grey shell debris are set within a mid-brown, Marlstone Rock ‘ferruginous limestone’ ferruginous matrix. Traces of cross-bedding are sometimes Occasionally, small lumps of the ore-grade ‘ironstone’ may be evident. found as rubblestone in building walls. This was originally a highly ferruginous ooidal limestone, which weathering has Marlstone Rock ‘ferruginous sandstone’ reduced to a mass of reddish-brown iron-oxide veins, with During the present survey, the name Marlstone Rock spheroidal ‘oo-moldic’ cavities. ‘ferruginous sandstone’ has been used for stone of similar texture to the ‘Sandrock’-like ferruginous sandstone, but with

Only dark Marlstone is used in the old Methodist church in Holwell.

Leicestershire Strategic Stone Study 23 Middle Jurassic The formation comprises a variety of decalcified ferruginous sandy limestones. The stones tend to be more vividly coloured Inferior Oolite Group (varying from the common yellow-brown to yellow-red, red-brown and purple-grey) and slightly coarser-grained than Northampton Sand Formation their Marlstone Rock Formation counterparts. Fossils, including large belemnites, are scattered throughout, and The Northampton Sand Formation crops out at the edge of distinctive U-shaped burrows cross-cut its fabric the uplands around Waltham on the Wolds, and caps the steep-sided hill summits east of Tilton and the broader hill at The Northampton Sand ‘ironstone’ is almost invariably used Nevill Holt. Small quarries exist and it was substantially as dressed stone, and less frequently as large ashlar blocks. It worked as an iron ore at Nevill Holt. There is no direct ranges from a poor to good quality freestone, and is generally evidence that it was quarried for building stone in the county, less susceptible to weathering than Marlstone Rock. It is used but its use in association with Nevill Holt Stone (see below) in village dwellings, churches, large houses (such as Launde suggests that they were extracted from the same locality. It is Abbey and Nevill Holt Hall), in restorations (for example at used extensively in villages in south-east Leicestershire, Stoughton church near Leicester), and for minor repairs. however, with most of the stone probably being imported from (below) is built from Northampton Sand the nearby Uppingham district of Rutland and from north ‘ironstone’, with minor repairs using the Marlstone Rock Northamptonshire. from .

A number of lithological variants may be seen in any one building, and all of these were probably obtained from a single quarry.

Launde Abbey.

Leicestershire Strategic Stone Study 24 Northampton Sand ‘ferruginous sandstone’ This ochreous brown, ferruginous sandstone can be confused with the dominant ‘Sandrock’ and Marlstone Rock lithologies. It is a porous stone, prone to exfoliation, producing rounded surfaces in extreme cases. The houses in Medbourne are built of Northampton Sand ‘ferruginous sandstone’, looking very similar to the ‘Sandrock’ of north-east Leicestershire (top right).

Northampton Sand ‘purple, bioturbated sandstone’ The houses in Medbourne are built of This is a purple- to purplish-grey hearted coloured, Northampton Sand ‘ferruginous sandstone. ferruginous, fine to medium-grained sandstone, characterised by darker, large U-shaped burrows of about 5mm in diameter. It may contain scattered bivalves, brachiopods, crinoid ossicles, calcareous ‘tubeworms’ (Genicularia vertebralis) and belemnites. This sandstone is seen in most of the Northampton Sand buildings examined, but only as a minor component. It is occasionally used decoratively e.g. for lintels and parapets, contrasting in colour with the walling stone, as at Nevill Holt school (bottom right).

Northampton Sand ‘shelly limestone’ This is a durable, shell debris-rich, dark buff limestone with a low iron content. It contains numerous crinoid ossicles, and occasionally shows thin, dark brown ferruginous partings. It is infrequently found as rubblestone in building walls, but is sometimes seen as dressed stone blocks.

Northampton Sand ‘ironstone’ Very rarely, this iron-rich stone is found as rubblestone. It displays a network of reddish-brown veins of iron oxide which traverse an ooidal, dark ochreous-brown ‘ironstone’ matrix.

Lincolnshire Limestone Formation Northampton Sand is occasionally used decoratively for lintels and parapets, as here at Nevill Holt School. The Lincolnshire Limestone Formation is a very important source of building stone, which has been worked since Roman times. Quarries in both the Lower and Upper Lincolnshire The formation includes a substantial range of lithologies, Limestone members occur along the outcrop from Lincoln which directly reflects variations in the relative proportions of through Rutland into Northamptonshire. Only the lower its constituents. These include ooids, pisoids, limestone member occurs in east Leicestershire, on the hill tops at pebbles, quartz sand, shells and shell debris, which may be Waltham on the Wolds in the north and Nevill Holt in enclosed in a matrix ranging from lime mud (micrite) to the south. translucent sparry cement. Many well-known building stones are named after the quarry location and type of rock worked e.g. Collyweston Slate, Wittering Pendle and Ancaster Rag. Leicestershire Strategic Stone Study 25 The limestones of the Upper Lincolnshire Limestone Member are more massively bedded and ooidal than those of the Lower Lincolnshire Limestone Member, and are often better sorted and better cemented. They are used throughout Leicestershire for dressings, quoins, repair work and in a few cases for entire building fabrics, such as the house and church at Stapleford Park. Shelly, spar-cemented limestones are the most durable stones and are used for drip courses. Well- cemented ooidal limestones, some with shell debris, are used as ashlar and also for decorative work and window mouldings. No attempt has been made in this survey to name specific varieties of Upper Lincolnshire Limestone, except for the distinctive Ketton Stone, of Rutland - a fine, well-sorted, even-grained ooidal limestone. Ketton Stone is a high-quality freestone, much sought after for dressings and the most delicate carvings.

LOWER LINCOLNSHIRE LIMESTONE MEMBER

Whilst the widely-used limestones of the Upper Lincolnshire The Church of St James the Greater in Leicester has a finely carved doorway of Upper Limestone Member have had to be imported from just over the Lincolnshire Limestone. county border, those of the Lower Lincolnshire Limestone Member are quarried within the county and only used close to their source in east Leicestershire. Three locally sourced stones have been identified in this survey:

Collyweston Slate This fine-grained, thinly-bedded, grey, sandy limestone is the source of the Collyweston ‘Slate’. The limestone is not a true slate, but is sufficiently thinly bedded to be split into suitable roofing stones. The limestones were dug from shallow mines, being brought to the surface in winter, wetted and exposed to the frost, which caused the stone to split into thin layers. The beds were quarried at Nevill Holt, where attempts to cut the stone mechanically failed. The main workings were around Collyweston in Northamptonshire, where a craft industry still produces small quantities of stone, but most tiles used now come from recycled sources. For roofing, the slates are rather heavy, so they are laid in diminishing courses, with the smallest at the ridge and the largest at the eaves. When weathered, the stone is pale greyish-yellow, often developing a patchy, darker grey lichen crust. Collyweston slates are found on a few houses in many villages in south-east Leicestershire, but are especially common in Medbourne, where the stone is A streaky appearance is shown by also used in thin slabs for the church yard wall. many Lincolnshire limestones. Leicestershire Strategic Stone Study 26 A pale yellow-buff coloured dwelling of Waltham Stone.

Nevill Holt Stone Field evidence seems to suggest that this distinctive limestone QUATERNARY overlies the basal Collyweston Slate unit, a supposition supported by its moderately extensive use in walls in PLEISTOCENE Medbourne and (near to Nevill Holt, where the Collyweston slates were once mined). It is found sporadically Pebbles/cobbles as far as Harcourt, 12 km away. It is a fine-grained, A variety of cobbles and pebbles have been transported into or sandy limestone with large ramifying, nodular burrows up to across the county by palaeo-rivers and glaciers. They are used 20 mm in diameter. The unweathered matrix colour is a very for minor infill and repairs in many of the older buildings, and pale grey-pink and the burrows are pale fawn. On weathering, sometimes for entire wall facings or as cobble paving. They however, shades of pale to mid brown develop, the matrix were probably gathered from local fields, and can be up to 30 becoming distinctly ochreous. cm in diameter (although most are less than 15 cm).

Waltham Stone The majority are large, highly rounded quartzite cobbles, with This is a fine-grained, compact, pale yellow-buff coloured, a brown rind, ‘generated’ originally in Triassic river systems micritic limestone with variable amounts of ooids, shells, and subsequently transported by glaciers during the Pleistocene. burrow traces and finely comminuted bioclastic debris. It is These very hard sandstones are occasionally face-dressed and extensively used in the village houses of Waltham on the rarely squared, exposing their pale grey interiors. Wolds, and , and for repairs in scattered locations across the north-east of the county. It is Some large sub-rounded cobbles of various Charnian used in moderately-sized, roughly squared blocks with the lithologies and the Ordovician diorites are also found, these surface left undressed. having been reworked and transported by ice. Rarely, small angular flints, ice-transported from further afield, have also In the church at Waltham on the Wolds, extensive use is made been used as building materials. of another variety of Lincolnshire Limestone - a cream to buff coloured, medium to coarse-grained, bioclastic, micritic limestone. It is strongly biotubated, with the irregular ochreous brown burrows being infilled with a softer grey limestone that readily weathers out to leave a pitted surface. The stone is used in large dressed blocks in various buildings in Waltham and the nearby village of Stonesby. Leicestershire Strategic Stone Study 27 The most extensive use of glacial erratics is in the south-west Calcareous Tufa of the county, especially to the south and west of Leicester and This is a highly porous, vuggy, low density, grey, freshwater south of Charnwood. Charnian cobbles are notable in garden limestone, which has fairly good load-bearing qualities. Tufa walls in Newtown Linford and the church at . The comprises a network of casts, formed by the precipitation of villages of Kimcote, and calcium carbonate (from spring water) around plant stems, illustrate the most striking use of Triassic pebbles (below). commonly reeds, or any other organic or inorganic fragments in the vicinity. It is rare in Leicestershire, and of very localised occurrence. It forms most of the facing and infill of the walls of the church ruins at the abandoned village of Knaptoft, south of Leicester. It was also used at in the far east-south- east of the county, where it is clearly visible in the cottage adjacent to the churchyard and is abundantly used in the church itself (although somewhat obscured by a partly removed lime render). In both cases, the source is unknown.

Cob This ancient building material is formed of mud and gravel with binding material such as chopped straw or animal hair. It has been used for barn and boundary walls in a number of villages in south Leicestershire, and in in the north-east of the county. Cob is prone to swelling if it gets wet, so walls are commonly given a capping of thatch or tiles, as seen in the village of Laughton (below).

Triassic pebbles.

Cob walls are commonly given a capping of thatch or tiles.

Leicestershire Strategic Stone Study 28 Imported Stone Late Permian

As already observed, the stone types most commonly used in Zechstein Group Leicestershire as ashlar and for dressings are in short supply, and much of what has been used has almost certainly been Cadeby Formation imported from neighbouring counties. Notable examples are Millstone Grit from Derbyshire, Bromsgrove Sandstone from Bulwell Stone Warwickshire and Staffordshire, Upper Lincolnshire Limestone Formerly known as the Lower Magnesian Limestone, this rock from Lincolnshire and Rutland, and Northampton Sand from was quarried extensively at Bulwell, immediately north-west of Rutland or Northamptonshire. One other relatively local stone Nottingham. Urban growth resulted in the closure of the has come in in smaller quantities from viz. quarries, however, and the limestone is now worked at only Bulwell Stone. Linby, a few miles to the north.

Cambro-Ordovician The stone was, and still is, supplied as either rubble-faced or sawn ashlar blocks. In colour, it is pale yellow with orange Welsh Slate tints, and can easily be recognised by virtue of its porous, The only relatively far-travelled import that is used to any great sacharoidal texture comprising coarse, rhombohedral crystals extent in Leicestershire is Welsh Slate. It was used for roofing of dolomite. It is durable, and is used for repair work and for buildings throughout the county during the 19th and 20th domestic garden walling at a few locations in the north of the century, replacing the local Swithland Slate. county, and for the entirety of St Stephens Church in Leicester.

The use of Welsh Slate on a church constructed of ‘Sandrock’.

Leicestershire Strategic Stone Study 29 Glossary

Ashlar: Stone masonry comprising blocks with carefully worked Igneous rock: Rocks formed when molten magma cools and beds and joints, finely jointed (generally under 6mm) and set in solidifies. It includes extrusive rocks erupted from volcanoes horizontal courses. Stones within each course are of the same (e.g. basalt) and intrusive rocks that cool beneath the Earth’s height, though successive courses may be of different heights. surface (e.g. granite, gabbro, granodiorite, dolerite). ‘Ashlar’ is often wrongly used as a synonym for facing stone. Ironstone: Sedimentary rock which is composed of more than Breccia: A sedimentary rock made up of angular fragments of 50% iron-bearing minerals. rock set within a finer-grained matrix. Lancet: A tall narrow window with a sharply pointed arched Buttress: A projection from a wall and bonded to the wall to head. A lancet window was a common feature of First Pointed or create additional strength and support. Early English Gothic architecture.

Calcareous: A rock which contains significant (10-50%) calcium Limestone: A sedimentary rock consisting mainly of calcium carbonate, principally in the form of a cement or matrix. carbonate (CaCO3) grains such as ooids, shell and coral fragments and lime mud. Often highly fossiliferous. Cobbles: Rounded rock clasts (of any lithology) between 64 mm and 256 mm in size. Lithology: The description of a rock based on its mineralogical composition and grain-size e.g. sandstone, limestone, Conglomerate: A sedimentary rock made up of rounded pebbles (>2mm), cobbles and boulders of rock set within a mudstone etc. finer-grained matrix. Micaceous: Applied to a rock which contains a significant proportion of mica, usually muscovite and/or biotite’. Cross-bedding: A feature principally of sandstones formed by the movement of sand grains in currents to produce layering Mudstone: A fine-grained sedimentary rock composed of a oblique to the margins of the beds. mixture of clay and silt-sized particles.

Dressings: To say a building is constructed of brick with stone Ooid: A spheroidal grain of calcium carbonate formed by dressings means that worked stone frames the corners and precipitation (by algae) of calcium carbonate in concentric openings of the structure. layers.

Dolerite: Medium-grained basic igneous rock found as small to Quartz: A commonly occurring crystalline form of silica (silicon medium sized intrusions. dioxide, SiO2). Dolomitic, dolomitised limestone: Descriptive term for a Quoin: The external angle of a building. The dressed alternate limestone that has had some or all of its calcium carbonate header and stretcher stones at the corners of buildings. replaced by calcium magnesium carbonate. Rubble: Rough, undressed or roughly dressed building stones Drip-mould: The projecting edge of a moulding, channelled, or typically laid uncoursed (random rubble) or brought to courses throated beneath, so that the rain will be thrown off. at intervals. In squared rubble, the stones are dressed roughly square, and typically laid in courses (coursed squared rubble). Facies: A term describing the principal characteristics of a sedimentary rock that help describe its mode of genesis e.g. Sandstone: A sedimentary rock composed of sand-sized grains dune sandstone facies, marine mudstone facies. (i.e. generally visible to the eye, but less than 2 mm in size).

Feldspar: A commonly occurring aluminosilicate mineral Sedimentary rock: A rock that is commonly formed by the variably containing potassium, sodium and calcium. binding together (lithification) of sediment particles (e.g. sandstone, siltstone, mudstone, limestone). Ferruginous: Containing iron minerals usually in the form of an iron oxide which gives the rock a ‘rusty’ stain. Siltstone: A sedimentary rock composed of silt-sized grains (i.e. only just visible to the eye). Fossiliferous: Bearing or containing fossils.

Freestone: Term used by masons to describe a rock that can be cut and shaped in any direction without splitting or failing.

Leicestershire Strategic Stone Study 30 Acknowledgements Further Reading

Written by Albert Horton and Julie Harrald, this study is part of Cantor, L. (2000). The Historic Parish Church of Leicestershire Leicestershire’s contribution to the Strategic Stone Study, and Rutland. Kairos Press. sponsored by Historic England. All images ©Julie Harrald. Carney, J. N. (1999). ‘Revisiting the Charnian Supergroup: New Edited by Graham Lott and Steve Parry, British advances in understanding old rocks’. Geology Today. Geological Survey. Blackwell Science Ltd. Based on the original design by Tarnia McAlester. Carney, J. N. (2000). ‘Igneous processes within late First published by English Heritage April 2012. This version of Precambrian volcanic centres near Whitwick, northwestern the atlas was rebranded by Historic England in December Charnwood Forest’. Mercian Geologist 15 (1), pp. 18-20. 2017. The information within it remains unaltered from the Carney, J. N. (2010). ‘Magma mixing in the South Leicestershire first version. Diorite: Evidence from an Ordovician pluton at Croft Quarry’. We are grateful for advice from the following: Mercian Geologist 17 (3). Don Cameron, British Geological Survey Carney, J. N’, Ambrose, K’, Cheney, C. S., Hobbs, P. R. N. (2009). Geology of the Leicester District, Sheet description of the Graham Lott, British Geological Survey British Geological Survey Sheet 156 Leicester (England and Steve Parry, British Geological Survey Wales). BGS. Keith Ambrose, British Geological Hoskins, W. G. (1972). The Heritage of Leicestershire. City of Leicester Publicity Department. John Carney, British Geological Survey Lott, K. G. (2001). ‘Geology and building stones in the East ’. Mercian Geologist 15 (2). Geological Society. McGrath, A. (2007). ‘The rock quarries of Charnwood Forest’. Mercian Geologist 16 (4). East Midlands Geological Society. Mee, A. (1947). ‘The King’s England – Leicestershire and Rutland’. Hodder and Stoughton Ltd. Pevsner, N. (1960). (revised by Williamson, E. & Brandwood, G.K., 1998). The Buildings of England – Leicestershire and Rutland. . Sutherland, D. S. (2003). Northamptonshire Stone. Dovecote Press. Whitaker, J. H. M. (2006). Building Stones of Leicester. East Midlands Geological Society. Whitehead, T. H., Anderson, W., Wilson V., Wray, D. A. (1952). The Liassic Ironstones. Memoirs of the Geological Survey of Great Britain. Her Majesty’s Stationery Office. Worssam, B. C. (1988). Geology of the Country around Coalville, Memoir for geological Sheet 155 (England and Wales). BGS.

British Geological Survey Maps & Brief Sheet Descriptions Geology of the Loughborough District, brief explanation of the geological map Sheet 141 Loughborough. (2002) BGS. Geology of the Melton Mowbray District, brief explanation of the geological map Sheet 142 Melton Mowbray. (2002) BGS. Geology of the Leicester District, brief explanation of the geological map Sheet 156 Leicester. (2002) BGS. Geology of the Coalville District, brief explanation of the geological map Sheet 155 Coalville. (2002) BGS.

Leicestershire Strategic Stone Study 31